Control mechanism



Jan. 23, 1951 w, w, WILLQUGHBY 2,539,217

CONTROL MECHANISM Filed July '7, 1948 Inventor: William W. Willoughby,

by is Attorney.

Patented Jan. 23, 1951 CONTROL MECHANISM WilliamzW-r.Willdughby, Hiltonvillage gva'z, as;

signor-rto General Electric-Company,- a c.orpora-.

ApplicationiJl'lly 7', 1948; SerialNo: 37:383.

My invention: relates:- to universal control: mechanisms provided-' with-a' universally-movable control handle on stick such -.as-- used in thecom I ti oli of "a.ircraftiaand the like and has forr. its ob jects-imple; reliable and efiioient:-means' for t r.e turning; the controlhandle to a: predetermined; neutral position by a. biasing force havingsultrstantiallythe same=values man positions of thei liandle 'thereby toreduce operating fatigue:

1 My: invention relates particularlyto an erec tlon":mechanism 1 for"centeringa' giinbal} mounted COl-Iti-fOR that' is" to operate electricdevices for-.- transmitting its movement to"- control mecha' nisms.

In smallairplanes the-'pilots'controls are connected to the controlsurfaces through mechanical linkages. The effect of the air upon thecontrol surfaces 5 is; communicated: back: through the linkage,affecting the easeofimovement of the controLstick-as the.pilotappliesv asignal to move the controls. This manifestation in the control-stick iscalled feel-1 The pilot when; ti alning in such aplane; learns to usethis feel aspart of his flying judgment:

The: conti' ol' surfaces -oflarge" aircraft due to their size must .be;operated electrically or hydraulically so that the control mechanismmere.- ly. transmits signals to a separate operating" means-instead of'being-itself connected wit'lrthe surfaces. Therefore, the feel of thecontrol stick is missing. Several methods have been used tosbring feelinto the control stick but Since each entails opposition to the pilotsmovement and causes fatigue, they are now left out. Even though in thebeginning of their training in large planes the pilots m ss feel asanoperational aid, they learn instead to base their judgment upon thechanging attitudes of the plane itself.

To take over control from the automatic pilot and operate the planemanually, the pilot throws a switch connecting in the control mechanismand operates the control stick. When manual control-is relinquished andthe control stick is released, it automatically returns to its neutralposition ready for resumption of control by the automatic pilot. Theattitude of the control stick" iniits neutral position during; straightand level flight is vertical, so that-fa control stick is. a normallyvertical member.

In accordance with my invention, the lower end of the extension of acontrol handle is constrained to move with the stem of the normallyvertical; centering member of a biasing mechathem. The centering memberhas a flat circular:

bases: perpendicular; to; its, stem:- which is positaken alongthea-brokenline-Zt-ZiofiEigz- 1 look:

ing in the; direction of. the arrows;: Fig; .3; is: a; plan: view. oftiles-plate: looking lll thei direction: ofithe; arrows; 3-3 Eig. at isa partial elevation? view-"of .the platewwith :thecontrolstick-deflected:

In the drawing, a control stick I ispivoted:

upontrunnions; 2." rotatable about. a. fixed pivot point la:: The.trunnions 2; arejournaled: in. a

gimbalfiiw'hich is pivotally mounted"on.a.sup-,-

porttcomposed ofbrackets 4 and; a. base -.5.:and are also rotatableabout'thepoi-nth lay. Rotation". about the t-tIUIl-I'liOIlZl operates aSelsyn -6- control-- ling -theelevators. of .an aircraft. Rotation; of.the"gimba-l=,3 operates:the, Selsynfl controlling;v combination; onailerons, and rudder; 0f the aircraft. Ann-extensionoi controlistick- Iendsin--a ball; 8 -that:*is constrainedwithin ansocket; in:thercylindrical stem of theeerectiommech. an-ism centering member; Illrito form a slidingball: and socket joint between thevcontrolistick'and,

the centering member. The stem of the centering member is perpendicularto a circular platen base II which tends to be restrained against theflat surface of the support in a recess 5 slightly larger than the baseof the member by a pressure plate I2 with an oversize hole through whichthe stem Ill projects. The recess in the base 5 prevents sidewisemovement of the base ll. A washer [3 around the stem keeps the base Hfrom entering the hole in the pressure plate. Where the centering memberpasses through the spacer and the plate the stem is modified into acircular bulge l4. Springs [5 r are 50 mounted around the periphery ofthe plate 9 as to bias the plate toward the base of the support. I

As the top of the control stick is moved in any direction, as shown bythe dotted outline in Fig. 1, the top of the centering member moves inthe opposite direction causing that member to pivot upon the bottom rimof its base. With the pivot point as a fulcrum the base tilts raisingthe spacer and plate against the spring. Upon release of the controlstick, the base is forced by a substantially flat surface, a centeringmember provided with a flat bottomed base normally seated on saidsurface, a slidable ball and socket joint between said handle and theend of said member opposite said base, a plate restraining meansprovided with an aperture through which said centering member extends,and springs biasing said plate means into engagement with said base soas to restrain said base against said flat surface.

2. A mechanism for centering a universally pivoted control handleprovided with a support having a substantially flat surface adjacentsaid handle, said mechanism comprising a centering member provided witha fiat bottomed base normally seated on said surface, a platerestraining means provided with an aperture through which said centeringmember extends, springs biasing said plate means into engagement withsaid base so as to hold said base against said fiat surface, and aslidable ball and socket joint formed on the end of said handle and theend of said member opposite said base and connecting said ends so thatwhen said centering member is seated fiat against said surface thecontrol handle is centered.

3. An automatic centering universal control mechanism comprising asupport provided with a substantially flat surface, a control handleuniversally pivoted about an intermediate point thereof, saidintermediate point being disposed in spaced relation to said flatsurface, a centering member provided with a fiat base normally seated onsaid flat surface, a slidable ball and socket joint connecting saidhandle and said member and means biased from said support and engagingsaid centering member whereby said flat base is restrained towardsengagement with said flat surface thereby to bias said handle to thecenter position thereof.

4. An automatic centering universal control mechanism comprising asupport provided with a substantially fiat surface, a control handleuniversally pivoted about an intermediate point thereof, saidintermediate point being disposed in spaced relation to said flatsurface, a centering member provided with a fiat base, a slidable balland socket joint connecting said handle and said member and means biasedfrom said support and engaging said centering member including a flatpressure plate engaging said centering member whereby said fiat base isrestrained towards engagement with said flat surface thereby biasingsaid handle to the center position thereof.

5. An automatic centering universal control mechanism comprising asupport provided with a substantially flat surface, a control handleuniversally pivoted about an intermediate point thereof, saidintermediate point being disposed in spaced relation to said flatsurface, a centering member provided with a fiat base, a slidable balland socket joint connecting said handle and said member, a flat pressureplate engaging said centering member and having a portion thereofprojecting around said member, a plurality of pins extending throughsaid projecting portion and spaced around the periphery of saidcentering member, each of said pins having an end thereof secured bysaid support and spiral springs surrounding said pins and biasing saidplate from the opposite ends of said pins whereby said flat base isrestrained towards engagement with said fiat surface thereby biasingsaid handle to the center position thereof. WILLIAM W. WILLOUGHBY.

REFERENCES CITED The following references are of record in the file ofthis patent:

